U.S. patent application number 10/693745 was filed with the patent office on 2004-05-06 for electric motor and brush retaining assembly.
This patent application is currently assigned to Ametek, Inc.. Invention is credited to Finkenbinder, David B., Marsden, Jeffrey D., Miller, R. Craig, Wu, Huanbo.
Application Number | 20040084992 10/693745 |
Document ID | / |
Family ID | 25516832 |
Filed Date | 2004-05-06 |
United States Patent
Application |
20040084992 |
Kind Code |
A1 |
Finkenbinder, David B. ; et
al. |
May 6, 2004 |
Electric motor and brush retaining assembly
Abstract
The present invention generally provides a motor-fan unit
including a motor assembly having a shaft, a commutator supported
on the shaft, and a pair of brushes in electrical contact with the
commutator, a fan assembly having an impeller coupled to the shaft,
an end plate assembly located between the impeller and the motor
assembly, said end plate assembly including a plate portion
defining an opening throughwhich the shaft passes, wherein said
commutator is located near the opening, and a pair of brush
retainers adapted to receive the brushes formed on the plate
portion adjacent said commutator, the brush retainers opening
toward the fan assembly.
Inventors: |
Finkenbinder, David B.;
(Ravenna, OH) ; Marsden, Jeffrey D.; (Stow,
OH) ; Miller, R. Craig; (Uniontown, OH) ; Wu,
Huanbo; (Cuyahoga Falls, OH) |
Correspondence
Address: |
Ray L. Weber
Renner, Kenner, Greive, Bobak,
Taylor & Weber
Fist National Tower, Fourth Floor
Akron
OH
44308
US
|
Assignee: |
Ametek, Inc.
|
Family ID: |
25516832 |
Appl. No.: |
10/693745 |
Filed: |
October 25, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10693745 |
Oct 25, 2003 |
|
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09970360 |
Oct 1, 2001 |
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6703754 |
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Current U.S.
Class: |
310/239 |
Current CPC
Class: |
F04D 25/06 20130101;
H02K 7/14 20130101; H02K 9/28 20130101; H02K 5/148 20130101 |
Class at
Publication: |
310/239 |
International
Class: |
H02K 013/00 |
Claims
1. A motor-fan unit comprising: a motor assembly having a shaft, a
commutator supported on said shaft, and a pair of brushes in
electrical contact with said commutator; a fan assembly having fan
coupled to said shaft; an end plate assembly located between said
fan and said motor assembly, said end plate assembly including a
plate portion defining an opening throughwhich said shaft passes,
wherein said commutator is located near said opening; and a pair of
brush retainers adapted to receive said brushes formed on said
plate portion adjacent said commutator, said brush retainers
opening toward said fan assembly.
2. The motor-fan unit of claim 1, further comprising a plurality of
resilient fasteners formed on any of said motor assembly, end plate
assembly and said diffuser assembly and corresponding receivers
formed on adjacent assemblies to effect tool free attachment
thereof.
3. The motor-fan unit of claim 1, further comprising a pair of
dividers extending axially from said plate portion toward said fan
assembly, said dividers being located on either side of said brush
retainers.
4. The motor-fan unit of claim 1, wherein said brush retainer is
generally U-shaped having a first member extending axially toward
said motor, a second member extending outward from said first
member and a third member extending axially toward said fan
assembly from said second member.
5. The motor-fan unit of claim 3, further comprising a notch formed
between said plate portion and said third member, said notch
extending radially along at least a portion of said portion of said
third member such that said third member terminates short of said
plate portion such that said brush retainer opens laterally of said
brush.
6. The motor-fan unit of claim 4, further comprising a support
member extending from said end plate portion toward said motor
assembly adjacent said third wall and in supporting relation
thereto.
7. The motor fan unit of claim 1, further comprising a spring
assembly in operative contact with said brush, whereby said spring
assembly urges said brush toward said commutator.
8. The motor fan unit of claim 6, further comprising a spring
holder extending from said end plate assembly receiving said
spring.
9. The motor fan unit of claim 7, wherein said spring has a first
leg and a second leg, said spring holder including a first
projection retaining said first leg, where in said second leg urges
said brush toward said commutator.
10. The motor fan unit of claim 8, further comprising a second
projection formed on said end plate assembly near said brush
retainer, whereby said second leg of said spring is receivable
against said second projection to insert or remove said brush
assembly.
11. The motor-fan unit of claim 1, further comprising a diffuser
located between said end plate assembly and said fan assembly, said
diffuser having an opening in fluid communication with said fan
assembly and throughwhich said shaft is received, said diffuser
further having a pair of brush cap assemblies corresponding to said
mouth of said brush retainers, said brush cap assemblies adapted to
be at least partially received within said brush retainers.
12. The motor-fan unit of claim 11, wherein said brush cap
assemblies each define a channel in fluid communication with said
fan assembly and open toward said brushes.
13. The motor-fan unit of claim 11, wherein said channel extends
radially substantially along the entire length of said brush.
14. The motor-fan unit of claim 11, wherein said diffuser assembly
further comprises at least one channeling member extending axially
toward said motor assembly, wherein at least a portion of said
projections extend axially toward said motor assembly beyond said
channeling members.
15. The motor-fan unit of claim 14, wherein said brush cap
assemblies are located adjacent a channeling member and wherein
said a channel of said brush cap assemblies is in fluid
communication with said opening, said brushes, and channeling
member, whereby air from the fan flows through said opening into
said channel across said brushes and out of said channel where it
is redirected by said channeling member.
16. The motor-fan unit of claim 11, wherein said brush retainer and
said end plate assembly define a notch adjacent said plate portion
and wherein said brush cap assembly has raised edge receivable
within said notch.
17. The motor-fan unit of claim 16, wherein said raised edge is
formed on said portion of said brush cap assembly extending into
said brush retainers.
18. The motor-fan unit of claim 17, wherein said raised edge
extends the length of said brush cap assembly.
19. The motor-fan unit of claim 11, further comprising a projecting
surface carried on said brush cap assemblies adapted to engage a
surface on said end plate adjacent said brush retainer upon
assembly such that said end plate assembly and said diffuser are
axially coupled.
20. The motor fan unit of claim 19, wherein said projecting surface
extend radially inward from said brush cap assemblies adjacent said
opening; and a commutator receiver formed on said end plate
coaxially aligned with said opening, said commutator receiver
defining at least one notch corresponding to said brush cap
assemblies and adapted to receive said projecting surface, said
notch having a surface that lockingly engages said projecting
surface upon insertion.
21. An end plate assembly in a motor-fan unit comprising: a plate
portion and a bracket portion adapted to be attached to the motor,
said plate portion having a commutator receiver formed thereon,
said commutator receiver defining a well that at least partially
receives said commutator.
22. The end plate assembly of claim 21, further comprising a brush
retainer integrally formed on said plate portion, said brush
retainer defining a mouth opening toward the fan of the motor-fan
unit.
23. The end plate assembly of claim 21, wherein said brush retainer
includes a generally U-shaped member extending axially toward the
motor from the plate portion about said mouth.
24. The end plate assembly of claim 23, wherein said brush assembly
includes a first member extending axially toward the motor from
said end plate a second member cantilevered from said first member
forming the base of said U and a third member extending axially
toward the fan from said second member, wherein said third member
terminates short of said plate portion to define a notch
therebetween.
25. The end plate assembly of claim 21 further comprising at least
one notch formed in said commutator receiver adapted to receive a
snap locking projecting surface.
26. A diffuser in a motor-fan unit having a motor assembly and a
fan assembly, the diffuser comprising: a plurality of channeling
members spaced about a central bore, and a pair of brush cap
assemblies extending axially toward the motor assembly.
27. The diffuser assembly of claim 26, wherein said assemblies
define a channel for receiving air from the fan assembly in the
motor-fan unit.
28. The diffuser assembly of claim 26, wherein said brush cap
assemblies include a projecting surface adapted to engage a surface
on an end plate assembly in a snap lock fashion to couple said end
plate assembly to the diffuser.
29. A combination diffuser assembly and end plate assembly in a
motor-fan unit having a motor assembly and a fan assembly
comprising: an end plate assembly having a plate portion; a pair of
brush retainers extending axially toward the motor assembly from
said plate portion defining a mouth that opens toward the diffuser
assembly; a pair of brush cap assemblies formed on the diffuser
assembly corresponding to said brush retainers and at least
partially extending into said mouth.
30. The combination diffuser assembly and end plate assembly of
claim 29, further comprising a channel formed in each of said brush
cap assemblies.
31. The combination diffuser assembly and end plate assembly of
claim 29, wherein said diffuser assembly and said end plate
assembly are attached by one or more resilient fastening
assemblies.
32. The combination diffuser assembly and end plate assembly of
claim 31, wherein said resilient fastening assemblies include a
projecting surface extending radially inward from said brush cap
assemblies adapted to engage a receiving surface formed on said end
plate assembly adjacent said brush retainers in a snap-locking
fashion.
33. The combination diffuser assembly and end plate assembly of
claim 30, said end plate assembly further comprising, a pair of
dividers located on either side of said each mouth.
Description
[0001] The present invention generally relates to electric motors
or generators. More particularly, the present invention relates to
electric motors having a brush assembly used to create an
electrical connection between a power supply and a commutator. Most
particularly, the present invention relates to a motor-fan unit
having an end plate and a diffuser that when assembled secure the
brush assembly in operative relation with the commutator.
BACKGROUND OF THE INVENTION
[0002] Electronic motors and generators are well known in the art
and have been put to use in a variety of applications. One
application is the handling of air. In these circumstances an
electric motor is coupled with a fan to create a flow or vacuum as
necessary. Often, the fan is used to provide cooling air to the
motor. In these instances, a fan mounted on a shaft driven by the
motor draws air into a fan shroud to compress or pressurize the
air. The pressurized air is released into the motor housing via one
or more ports which direct the air across the motor windings to
draw heat into the flow and exhaust it from the motor housing.
[0003] The motor includes several components including field
windings, that surround a centrally located shaft, which is
rotatably mounted in suitable bearings. A commutator is mounted on
the shaft and placed in electrical contact with a power supply by a
pair of opposed brushes contacting the commutator. In most motors
found in the industry, the motor's components are supported on a
skeletal frame, which is often made of metal to provide adequate
support. Recently, non-metal molded motor frames and housings have
been used to reduce the weight of the motor and reduce the leakage
prevalent in skeletal designs. In either case, the commutator
brushes must be supported by the motor frame. In skeletal frames, a
shelf is provided adjacent the commutator with the brush supported
thereon. A U-shaped clip is placed over the brush and fastened to
the shelf, by screws, to secure the brush next to the commutator.
In the non-metal frames, tube-like fittings are provided to support
the brushes. These fittings add complexity to the molding of the
motor components and often require the use of mandrels or
sacrificial molding techniques. While it is desirable to use molded
products in the construction of motor-fan assemblies to reduce
leakage and improve efficiency, the additional complexity of
molding the brush fittings reduces the ability of such devices to
remain cost effective. Additionally, these fittings are closed off
from the cooling air stream reducing the heat transfer rate at the
brushes. The reduced heat transfer at the brushes, thus, reduces
the efficiency of the motor. Therefore, there is a need for a
motor-fan unit that addresses at least one of these deficiencies in
the art.
SUMMARY OF THE INVENTION
[0004] It is, therefore, an object of the present invention to
provide a motor-fan unit employing a more simply molded brush
retainer. It is another object of the present invention to provide
a brush retainer that is formed such that it is open in the axial
direction.
[0005] Another object of the present invention is to provide a
motor-fan unit having a brush retainer that is in fluid
communication with the air flow generated by the fan, such that the
brush receives cooling air therefrom.
[0006] In view of at least one of these objects, the present
invention generally provides a motor-fan unit including a motor
assembly having a shaft, a commutator supported on the shaft, and a
pair of brushes in an electrical contact with the commutator, a fan
assembly having an impeller coupled to the shaft, an end plate
assembly located between the impeller and the motor assembly, said
end plate assembly including a plate portion defining an opening
throughwhich the shaft passes, wherein said commutator is located
near the opening, and a pair of brush retainers adapted to receive
the brushes formed on the plate portion adjacent said commutator,
the brush retainers opening toward the fan assembly.
[0007] The present invention further provides an end plate assembly
in a motor-fan unit including a plate portion and a bracket portion
adapted to be attached to the motor, the plate portion having a
commutator receiver formed thereon, the commutator receiver
defining a well that at least partially receives the
commutator.
[0008] The present invention further provides a diffuser in a
motor-fan unit including a plurality of channeling members spaced
about a central bore, and a pair of brush cap projections extending
axially motor in toward the motor-fan unit.
[0009] The present invention further provides a combination
diffuser assembly and end plate assembly in a motor-fan unit
including an end plate assembly having a plate portion, a pair of
brush retainers extending axially toward the motor from the plate
portion defining a mouth that opens toward the diffuser assembly, a
pair of projections formed on the diffuser assembly corresponding
to the brush retainers and at least partially extending into the
mouth.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a partially sectioned front elevational view of a
motor-fan unit according to the present invention with the cover
removed to show details of the motor assembly, end plate assembly,
diffuser assembly, and fan assembly;
[0011] FIG. 2 is an exploded perspective top view of the motor-fan
unit according to the present invention depicting details of the
motor assembly, end plate assembly, diffuser assembly, and fan
assembly;
[0012] FIG. 3 is an exploded perspective bottom view of the
motor-fan unit according to the present invention depicting details
of the motor assembly, end plate assembly, diffuser assembly, and
fan assembly;
[0013] FIG. 4 is a plan view of the end plate depicting details of
the motor-side of the end plate;
[0014] FIG. 5 is a front elevational view of the end plate assembly
depicting further details of the end plate assembly, including a
brush retainer assembly and motor attachment brackets;
[0015] FIG. 6 is a partially sectioned right side elevational view
of the end plate assembly depicting details of the commutator
receiver;
[0016] FIG. 7 is a perspective view of the end plate assembly
depicting further details of the motor-side thereof, including the
location of the brush retainers adjacent the commutator
receiver;
[0017] FIG. 8 is an enlarged partially sectioned side elevational
view as might be seen along line 8-8 in FIG. 4 depicting details of
a brush retainer according to the present invention;
[0018] FIG. 9 is a plan view of an end plate according to the
present invention depicting details of the diffuser side of the end
plate assembly;
[0019] FIG. 10 is a plan view of a radial diffuser according to the
present invention depicting a pair of brush cap assemblies located
adjacent the central bore of the diffuser;
[0020] FIG. 11 is a front elevational view of a radial diffuser
according to the present invention depicting the brush cap
assemblies extending axially inward to protrude beyond the radial
channel members located on the diffuser;
[0021] FIG. 12 is a side elevational view of a radial diffuser
similar to that depicted in FIG. 10 depicting details of the brush
cap assemblies, including a channel formed within each cap assembly
to direct air toward the brushes in the motor-fan unit;
[0022] FIG. 13 is a perspective view of a radial diffuser according
to the present invention depicting brush cap assemblies extending
from the surface of the diffuser adjacent the central bore having
air channels that cooperate with an adjacent diffuser channel;
[0023] FIG. 14 is a plan view of a radial diffuser similar to that
shown in FIG. 10 depicting details thereof, including a planer
surface above which the fan of the motor-fan unit rotates drawing
air through the circumferential inlets located about the
surface;
[0024] FIG. 15 is a perspective view of an end plate and radial
diffuser according to the present invention shown attached to
depict details of the cooperation of the brush retainer and brush
cap assembly located on the respective end plate and diffuser to
form a brush retaining enclosure that channels air to the brushes
via the channel formed in the cap assembly;
[0025] FIG. 16 is a plan view of a ported diffuser according to the
present invention depicting a pair of brush cap assemblies located
adjacent the central bore of the diffuser;
[0026] FIG. 17 is a front elevational view of a ported diffuser
according to the present invention depicting the brush cap
assemblies extending axially inward to protrude beyond the radial
channel members located on the diffuser;
[0027] FIG. 18 is a side elevational view of a ported diffuser
similar to that depicted in FIG. 10 depicting details of the brush
cap assemblies, including a channel formed within each cap assembly
to direct air toward the brushes in the motor-fan unit;
[0028] FIG. 19 is a perspective view of a ported diffuser according
to the present invention depicting brush cap assemblies extending
from the surface of the diffuser adjacent the central bore having
air channels that cooperate with an adjacent diffuser channel;
[0029] FIG. 20 is a top plan view of a ported diffuser similar to
that shown in FIG. 10 depicting details thereof, including a planer
surface above which the fan of the motor-fan unit rotates drawing
air through the circumferential inlets located about the surface;
and
[0030] FIG. 21 is a perspective view of an end plate and ported
diffuser according to the present invention shown attached to
depict details of the cooperation of the brush retainer and brush
cap assembly located on the respective end plate and diffuser to
form a brush retaining enclosure that channels air to the brushes
via the channel formed in the cap assembly;
[0031] FIG. 22 is a perspective view of a radial diffuser according
to the present invention enlarged to show details of an alternative
brush cap assembly having snap-lock projections located thereon to
effect attachment of the end cap assembly to the diffuser assembly;
and
[0032] FIG. 23 is an enlarged perspective view of an end plate and
radial diffuser according to the present invention having brush cap
assemblies with snap lock projections that engage surfaces on the
commutator receiver of the end plate to couple the end plate to the
diffuser.
DETAILED DESCRIPTION OF THE INVENTION
[0033] A motor-fan unit, generally indicated by the numeral 10 in
the accompanying FIGS., generally includes a motor assembly 15 and
a fan assembly 25. Since motor and fan assemblies 15,25 are widely
used in the art, only a general description of their components
will follow. As shown in FIG. 1, the motor-fan unit 10 includes an
electric motor 16 with an armature or winding 17, a commutator 18,
and brushes 19 which provide a connection from the power source to
the commutator 18 and the windings 17. A shaft 20 is supported on
suitable bearings such that it is freely rotatable and is connected
to the commutator 18 so as to rotate therewith.
[0034] As shown in FIG. 1, the motor assembly is configured with
the commutator 18 closest to the fan assembly 25. The fan assembly
25 of motor-fan unit 10 includes a fan 26 coupled to one end 27 of
shaft 20, as by nut, such that it rotates therewith. The fan
assembly 25 further includes a shroud 30 that encapsulates the fan
26. As is known in the art, the shroud 30 is provided with an axial
aperture through which outside air is drawn by the fan 26. In the
embodiment shown, shroud 30 includes a centrally located port 31
formed in a cover portion 32 of shroud 30 coaxially located with
the axis A of shaft 20. The air is exhausted by the fan 26 which is
received by a diffuser (to be described in detail later) which
distributes the air as needed by the end use.
[0035] With reference to FIGS. 2-9, motor assembly 15 may be
provided with an end plate assembly, generally indicated by the
numeral 35, to enclose the motor and support brushes 19. The end
plate assembly 35 generally includes a planar plate portion 36,
which may be annular as shown, and, a motor bracket portion 37
extending from the plate portion toward the motor 16. As best shown
in FIG. 4, the bracket portion 37 is adapted to support the motor
assembly 15. A fastening plate33 has tabs 34 with holes
therethrough for receiving fasteners that are secured into the
receivers 38. The fasteners and the fastening plate 33 secure the
motor assembly 15 to the end plate 35.
[0036] End plate assembly 35 defines a central opening 39 which
receives the shaft 20. Since, as shown in FIG. 1, the commutator 18
is located on the shaft 20 adjacent the end plate assembly 35, the
end plate assembly 35 may be provided with a commutator receiver,
generally indicated by the numeral 40, that receives commutator 18
and provides suitable clearance for the rotation of the commutator
18. As shown in FIG. 5, the commutator receiver 40 may bulge
axially outwardly of plate portion 36 defining a well 41 in which
at least a portion of the commutator 18 resides. Well 41 may also
receive bearings (not shown) used to support shaft 20 such that it
is freely rotatable. As shown, the commutator recess 40 may include
a plurality of stepped concentric recesses 42, 43, 44, to
accommodate the profile of the commutator 18 and bearings 21. In
this way commutator 18 may be placed close to the fan assembly 25
and receive cooling air prior to the air's passage over the
windings. In this way, the commutator 18 is more efficiently cooled
improving the motor's performance.
[0037] Since, during the operation of the motor-fan unit 10, the
brushes 19 contact commutator 18, end plate assembly 35 is provided
with a pair of brush retainers, generally indicated by the numeral
50. The structure of each brush receiver 50 is largely identical
with one being a mirror image of the other. Consequently, a
description of only a single brush retainer 50 will follow. As best
shown in FIGS. 4-8, the brush retainer 50 may be in the form of a
channel-like member having three contiguous walls or members 51,
52, 53 that form open ends 54 to cradle the brush 19. Preferably,
the retainers 50 face the motor assembly 15 to ease molding
thereof. As shown in the Figures, brush retainer 50 opens toward
the fan assembly 25 in a mouth 55 formed in the plate portion36. A
projection in the mold cavity may be used to create the open
retainer 50. It will be appreciated that by providing an open
retainer 50, mold design is greatly simplified and the use of
sacrificial molding or subsequent machining necessary to create
tubular brush retainers as used in the art is obviated, thereby
reducing mold cycle time. Further, the formation of an open
resilient type brush retainer 50 allows interference fitting of the
brush 19 within the receiver 50 eliminating the use of retaining
clips which are commonly used when attaching the brushes to a motor
housing. As an alternative to the channel-like brush retainer 50
shown, suitable brush retainers 50 might include an L-shaped member
or one or more posts used to locate the brush 19. The channel-like
retainer 50 shown, may be formed as a single piece or have spaced
portions suitably supporting the brush 19.
[0038] In the embodiment shown, brush retainer 50 has a first wall
51 extending axially inward from the end plate 35, a second member
52 extending outward from and generally at a right angle to the
first member 51. The second member is axially spaced from the plate
35 to define a vertical suitable clearance 56 for brush 19, and a
third member 53 or tab extending axially toward the plate portion
36 to define a horizontal clearance 57 for receipt of brush 19. As
discussed members 51, 52, 53, may be spaced such that clearances
56, 57 create an interference fit between the brush 19 and retainer
50. As shown in FIG. 8, the third member 53 may not connect to the
plate portion 36 leaving a gap or notch 58 between the plate
portion 36 and the third member 53 along one side of the brush 19.
A support member 59, such as a post, may extend axially from the
plate 39 to support the cantilevered second and third member 52, 53
opposite first member 51. In the embodiment shown, the support
member 59 is placed adjacent the brush retainer 50 near the edge 61
of retainer 50 closest to the commutator receiver 40. At this
location, the support member 59 may further aid the brush retainer
50 in maintaining the position of the brush.
[0039] To ensure good contact between the brush 19 and commutator
18, the brush 19 biased into engagement with the commutator 18. To
that end, a spring generally indicated by the numeral 60 may be
used. Consequently, end plate 35 may be provided with a spring
holder, generally indicated by the numeral 65 on which spring 60 or
other biasing member is mounted. In the embodiment shown, a coil
spring 60 having a coil 61 a first leg 62 and a second leg 63 is
employed to bias the brush 19 toward commutator 18. The coil 61 is
press fit over spring holder 65 and the first leg 62 is fixed with
a suitable clip such as the spring retaining first projection 66
formed on the surface of plate 35. While the first projection 66
may simply be a wall, an L-shape projection may be used, as shown,
to hold the first leg 62 against the torsional force of the coil
spring 60 and further prevent the first leg 62 from moving axially
beyond the first projection 66 and coming free thereof. The second
leg 63 is rotated such that it contacts the rear of brush 19 to
urge it toward the commutator 18. Since the brush 19 may be
inserted after the assembly of the motor 15, it may be necessary to
preload the spring 60 to hold it in place. To that end, a second
projection 68 may be provided on the surface of end plate 35 or on
the spring retainer 50, as shown. Second projection 68 is located
such that the second leg 63 of spring 60 is compressed creating
torsional force within the spring 60 sufficient to hold the second
leg 63 against the second projection 68. In the embodiment shown,
an L-shape second projection 68 extends axially inward from the
second member 52 of brush retainer 50 defining a recess 69 in which
the end 71 of second leg 63 may be inserted to assume a preloaded
condition 60' (FIG. 4). When the brush 19 is in place within
retainer 50, the second leg 63 is compressed to clear the brush
retainer 50 and any extending portion of the brush 19 and then
placed in contact with the rear of brush 19 to urge the brush 19
toward commutator 18.
[0040] As previously mentioned, the brush retainers 50 are formed
as open structures defining a mouth 55 within the end plate 35 that
opens toward a diffuser assembly 80 and additionally extends into a
portion of the commutator recess 40. The opening 55 allows cooling
air from the fan assembly 25 to flow to the brushes 19, as will be
described more completely below. A pair of cavities 75 are formed
in the end plate 35 to direct air over the windings 17 or other
parts of the motor assembly 15 as necessary. As shown in FIG. 9,
these cavities 75 may be at least partially sealed from the mouth
55, to prevent particulate from the brushes 19 from being carried
into the downstream areas of the motor assembly 15. To further
prevent passage of particulate matter, dividers 76, 77 extend from
the plate 37 and may comprise a bead or material extending adjacent
cavities 75 between the cavities 75 and the mouth 55 of brush
retainer 50. As shown, the dividers 76, 77 generally cordon off a
sector surrounding each of said mouths 55 and cavities 75such that
the plate portion is fluidically separated into four distinct
portions.
[0041] Air from the fan assembly 25 may be distributed, as by a
diffuser assembly, generally indicated by the numeral 80. In
accordance with the concepts of the present invention, a
radial-type diffuser assembly 80A (FIGS. 10-15) or a ported type
diffuser assembly 2, 3 and 80B (FIGS. 16-20) may be used. For the
purposes of this invention, these diffuser assemblies 80A, 80B are
interchangeable and are comprised of generally the same basic
components. Notable distinctions between the ported and radial
diffusers will be noted in the FIGS. by using a numeral and letter
combination to indicate components characteristic of the radial or
ported diffuser assemblies 80A, 80B respectively. For general
reference, the diffuser assembly will be referred to by the numeral
80. Further, the blades 86A,87B or channels 86B,87B formed on such
a diffuser assembly 80 may be of any number or configuration as
required by the particular application for the motor-fan unit 10.
Since the differences between the radial and ported diffusers 80A,
80B are largely inconsequential for purposes of the present
invention, similar numbers will be used to refer to similar parts
of each diffuser 80A, 80B.
[0042] Both of the diffusers 80A, 80B generally have a planar base
member 81, which may be made annular to define a bore 82 about axis
A. Blades 86A, 87A or channels 86B, 87B, collectively referred to
as channeling members 83 extend from one or more of the base
member's sides 84, 85. In this regard, the radial diffuser 80A and
ported diffuser 80B are distinguished in that the structures used
to channel the air drawn into the motor-fan unit 10 and the
structures used to channel that air as it is pressurized by the fan
assembly 25 differ. In particular, the radial diffuser 80A includes
a plurality of circumferential blades 86B surrounding the fan 26
that are used to guide the air outwardly from the fan side 85,
wherein a portion may be directed externally of shroud 30 through a
plurality of ports 34 provided in the shroud 30. A second set of
blades 87A formed on the motor-side 84 of the radial diffuser 80A
channels a remaining portion of the air radially inwardly toward
the center of the diffuser 80A. The blades 87A may be configured in
any pattern, as required by the particular application, including
the spiral or pinwheel pattern shown. In contrast to the radial
diffuser 80A, a ported diffuser 80B has enclosed channels 86B, 87B
formed in similar patterns to the blades 86A, 87A (pinwheel) to
channel all the incoming and outgoing air as described above, but
the shroud is completely enclosed.
[0043] Diffuser assemblies 80 are provided with a pair of brush cap
assemblies 95 that coact with the brush retainer 50 to trap brush
19 therebetween. In general, brush cap 95 is a surface that
substantially closes the open side 55 of brush retainer 50. To
contact the brush 19 or otherwise penetrate the opening, the brush
cap 95 may extend axially, taking on the form of a projection,
toward the motor assembly beyond the channeling members 83, to a
desired extent. Preferably, the brush cap 95 will not extend such
that its contact with brush 19 would interfere with the proper
assembly of the motor-fan unit 10. The brush cap 95 generally
conforms to the contours of brush retainer mouth 55 and may be
toleranced to provide a clearance that would allow dust from the
brush 19 to escape through end 54 of retainer 50 facing commutator
18, during operation of the motor-fan unit 10. By doing so dust
build-up on the brushes 19 is reduced, and the air flow cools the
brushes 19 extending brush life. Further, the air escaping the
brush retainer 50, defined by post 59 and walls 51, 52 at the
radial interior extreme of retainer 50 at end 54 facing commutator
18, flows over commutator to cool the commutator 18 improving motor
efficiency.
[0044] In the embodiment shown in FIGS. 1-21 brush cap assembly 95
has a generally rectangular shape to conform to the rectangular
opening in the end plate assembly 35. Alternatively, as shown in
FIGS. 21 and 22,a portion of brush cap assembly 95 may be provided
with a projection surface to perform a coupling function, as will
be described below. To channel air from the fan assembly 25 toward
the brushes 19, brush cap 95 may be provided with channels 93
formed in a brush cap assembly. In the embodiment shown, channels
93 are formed between a pair of upstanding members 96, 97 formed on
the motor side 84 of diffuser 80A. Members 96, 97 are generally
located adjacent the central opening 82 and may radially project to
an extent into the opening as best shown in FIGS. 14 and 19. To
accommodate the extension of the brush cap members 96, 97 into
opening 82, recess openings 98 may be formed on the commutator
receiver 40, as shown in FIG. 2. Advantageously, the extension of
members 96, 97 an interference of friction fit between the members
96, 97 and commutator receiver 40 may be used in coupling the end
plate 35 and diffuser 80.
[0045] The first and second members 96, 97 are of a similar height
to the blades 87 in the radial type diffuser 80A to allow proper
attachment of the diffuser 80A to the end plate 35. First and
second members 96, 97 may extend axially inward beyond the blades
87A to an extent such that they extend into the openings 75 defined
by brush retainers 50. First member 96 may have a raised edge 99
sized to fill the notch 58 between the plate portion 36 and the
third member 53 of brush retainer 50. In this way, the brush cap
assembly 95 encloses the brush 19 when the end plate 35 and
diffuser 80A are coupled to one another. Adjacent the raised edge
99, the first member 96 may be provided with a landing 100 having
the same height as second member 97 forming a recessed area that
lies adjacent to the brush 19 when the diffuser 80A and end plate
35 are joined. The channel 93 opens toward motor assembly 15
between landing 100 and second member 97 to distribute air
generated by the fan assembly 25 across the exposed surface 101 of
the brush 19 lying adjacent brush cap 95. The air channeled through
the channel 93 helps to transport heat away from the brush 19
benefitting the motor's efficiency. A truncated blade 102A or
truncated channel 102B, in a ported diffuser 80B, lies radially
outward and immediately adjacent to the assembly 95 and may be
formed adjacent first member 96. The blade 102A is shaped similar
to blades 87A and channels the air entering the channel 93 toward
central opening 82, as indicated by the arrows (FIG. 13). To
receive the raised surfaces of end plate assembly 35 adjacent to
assemblies 95, one or more of the blades 87A may be provided with a
notch 103. In the embodiment shown in FIG. 13, the notches 103
occur on the blades 87A located adjacent the truncated blades 102A
in the clockwise direction.
[0046] The ported diffuser 80B has similar assemblies 95 that, as
best shown in FIG. 3, extend axially inward of the planar portion
104 of diffuser assembly 80B. Here, the brush cap assemblies 95 are
only distinguished in that they are surrounded by channels 87B as
opposed to blades 87A. Truncated channel 102B, has smaller overall
dimensions than channels 87B and undergoes a sharper radiused turn
at 105 to accommodate the brush cap assemblies 95.
[0047] In either diffuser 80A, 80B, brush cap assemblies 95 may be
used in coupling diffuser 80 to end plate 35. As described, a
friction fit between brush cap assembly 95 and the walls of opening
55 or surfaces of commutator receiver 40 may help couple diffuser
80 and end cap 35. Alternatively, as best shown in FIGS. 22 and 23,
brush cap assembly 95 may be provided with a projecting surface,
generally indicated by the numeral 110, that performs a snap
locking function in connection with a surface 111 of end cap 35. It
will be appreciated that projecting surface 110 may be one of a
number of configurations commonly used in the art to perform a snap
locking function including a flexible tab, a rounded surface, or a
tapered leading surface 112 and stop surface 113 combination as
shown. As shown in FIG. 21, brush cap assemblies 95 may have
triangular projections 115 extending radially inward from each
member 96,97. The tapered surface 112 of projection 115 slopes
outwardly from a member 96 or 97 toward diffuser 80. The stop
surface 113 extends inwardly from the tapered surface 12 and is
located vertically on members 96 or 97 to provide a clearance at
116 for the receipt of a portion of the commutator receiver 40.
When assembling diffuser 80 and end cap 35, the tapered surface 112
cause gradual deflection of either members 96, 97 and /or the wall
of commutator receiver 40 such that upon the passage of tapered
surface 112, m the wall rebounds into the clearance 116 beneath
stop surface 113 with an audible indication to the assembler. Stop
surface 1 13 engages surface 111 such that end cap 35 and diffuser
80 are not free to move apart coupling these components. While a
radial diffuser is shown in FIGS. 22 and 23, snap-lock brush cap
assemblies 95 may be used on a ported diffuser 80B, as well.
Additionally, similar projections may be formed on other components
of the present invention to effect tool free attachment
thereof.
[0048] It should now be understood that a new and useful motor-fan
unit has been disclosed in accordance with the patent laws. It will
further be understood that various modifications and substitutions
may be made in the described invention without the departing from
the spirit thereof, and, to appreciate the scope of the invention,
reference should be made to the following claims.
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